2-aryl-4-amino-5-cyano pyrimidine derivatives

ABSTRACT

COMPOUNDS OF THE FORMULA:   2-(R1-PHENYL),4-R2,5-X,6-((R3,R4-PHENYL)-N(-R)-)PYRIMIDINE   IN WHICH R, R1 AND R2 ARE INDEPENDENTLY SELECTED FROM THE GROUP, CONSISTING OF -H AND LOWER ALKYL RADICALS, R3 AND R4 ARE INDEPENDENTLY SELECTED FROM THE GROUP CONSISTING OF -H, LOWER ALKYL AND LOWER PERFLUOROALKYL RADICALS, X IS A MEMBER SELECTED FROM THE GROUP CONSISTING OF -CN AND   1H-TETRAZOL-5-YL   RADICALS, AND PHARMACEUTICALLY ACCEPTABLE ACID ADDITION SALTS THEREOF, POSSESS CENTRAL NERVOUS SYSTEM DEPRESSANT AND ANTI-INFLAMMATORY PROPERTIES WHEN ADMINISTERED TO WARM BLOODED ANIMALS.

United States Patent 3,816,423 Patented June 11, 1974 3,816,423 2-ARYL-4-AMlN0-S-CYANO PYRIMIDINE DERIVATIVES Dong H. Kim, Wayne, and Arthur A. Sanfilli, Havertown, Pa., assignors to, American Home Products Corporation, New York, N.Y. No Drawing. Filed Aug. 31, 1972, Ser. No. 285,153 Int. Cl. C07d 51/42 US. Cl. 260-256.4 N

3 Claims ABSTRACT OF THE DISCLOSURE Compounds of the formula:

l NR radicals, and

pharmaceutically acceptable acid addition salts thereof, possess central nervous system depressant and anti-inflammatory properties when administered to warm blooded animals.

BRIEF DESCRIPTION OF THE INVENTION In accordance with this invention there is provided a new means for inducing central nervous system depressant activity and anti-inflammatory activity in warm blooded animals by administering to the animals an effective dose of one or more members of the compound aspect of this invention as depicted by the formula:

in which R, R and R are independently selected from the group consisting of H and lower alkyl radicals,

R and R are independently selected from the group consisting of H, lower alkyl and lower perfluoroalkyl radicals,

X is a member selected from the group consisting of CN and N-N ll N-N H radicals, and

pharmaceutically acceptable acid addition salts thereof.

The compounds of this invention are prepared by reaction of an appropriately substituted benzamidine hydrochloride NH @ii-Nm-Hm RI with a compound of the structure:

CN mo -0:0

r coiEt to afford the 2-aryl pyrimidine heterocycle @kN 0H which is readily converted to the 4-halo substituted derivative by reaction with a reagent such as POCl PO1 PCI;,,

and the like. The 4-halo pyrimidine derivative reacts smoothly with amines of the formula:

and subsequently with an azide, such as sodium azide, to produce the lg-tetrazole of the structural formula:

to yield IR. N-N

R N H @h NE A in which the groups R, R and R are independently selected from the group consisting of --H and lower alkyl radicals;

R and R are independently selected from the group consisting of H, lower alkyl and lower perfluoroalkyl radicals,

An alternative route to the intermediate 4-halopyrimidines, and the preferred synthesis of a 5-cyano4-halo derivative, involves the conversion of a 5-carboalkoxy-4- hydroxy-Z-aryl-pyrimidine to the 5-carbamyl derivative by treatment with concentrated ammonium hydroxide in a sealed steel bomb at steam bath temperature. The resulting amide is converted to the 5-cyano4-halo product in high yield by refluxing it with a large excess of -POCl (J. Heterocycl. Chem., vol. 8, pp. 715-719 (1971)).

The pharmaceutically acceptable acid addition salts are prepared by conventional processing of the base with those non-toxic acids, organic or inorganic, known to be acceptable in formulation of compounds for oral and parenteral administration, such as hydrochloric, hydrobromic, sulfuric, phosphoric, methane sulfonic, nitric, ptoluene sulfonic, acetic, citric, maleic, succinic and the like.

The term lower alkyl is used throughout this specification to define straight and branched chain monovalent hydrocarbon radicals containing from one to 7 carbon atoms such as methyl, ethyl, i-propyl, n-priopyl, n-butyl, n-hexyl, and the like.

Both the 5-(IE-tetrazol-S-yl)pyrimidine derivative of this invention and the 5-cyano-4-m-trifluoromethylanilinopyrimidine precursor exhibited central nervous system depressant activity at dosage levels as low as 40 milligram per kilogram body weight when administered intraperitoneally to three mice at each of the dosage levels 400, 127, 40 and 12.7 milligrams per kilogram host body weight. The activity was observed by watching the test mice for a minimum of two hours during which time any signs of general stimulation (i.e. increased spontaneous motor activity, hyperactivity on tactile stimulation, twitching), general depression (i.e. decreased spontaneous motor activity, decreased respiration and autonomic activity (i.e. miosis, mydriasis, diarrhea) were noted. The 5-cyano- 4-m-t1ifluoromethylanilino-pyrimidine derivative demonstrated central nervous system activity as a depressant with marked decrease in motor activity, decreased respiration and ataxia, while the S-(IE-tetrazol-S-yl) pyrimidine derivative exhibited decreased respiration and motor activity without indication of ataxis. Thus, depressant activity is induced at dosage levels well below that found to be excessive.

The compound, 2-phenyl-4-(a,a,w-trifluorom-toluidino)-5-pyrimidinecarbonitrile, exhibits anti-inflammatory activity evidenced by diminished swelling of carrageenin induced edema. Thus, a 43 percent inhibition of experimentally induced edema in the hind paw of male rats weighing from 120-160 grams was observed. -In practice, from 1.0 to 100 milligrams of the compound being tested per kilogram body weight of the rat was administered orally to six rats with a six rat control being administered aqueous vehicle with no active compound. Sixty minutes after drug administration, edema was induced by injection of 0.05 milliliters of 1 percent carrageenin solution in saline into the subplanar tissue of the rats right hind paw. The paw volume was immediately volumetrically determined with a plethysmograph and again 3 hours later. The mean volume swelling for the control group was determined and compared to the test group. Swelling inhibition of 23 percent or more is considered to be indicative of an active compound.

The compound, 2-phenyl-5-1g-tetrazol-5-yl)-4-(a,a,! trifluoro-m-toluidino)pyrimidine, displayed moderate anti-inflammatory activity (more than 20 percent change at one millimolar concentration) when examined in vitro for albumin denaturation inhibition in a manner similar to that of Mizushima, Arch. int. Pharmacodyn, 149, 1-7 (1964); acceleration of a disulfide-sulfhydryl interchange in serum albumin when examined in a manner similar to that of Gerber et al., Biochem, Pharmacol, 16, 115-123 (1967); and inhibition of aldehyde binding to albumin when examined in a manner similar to that of Skidmore et al., J. Pharm. Pharmacol. 17, 671-673 (1965).

Thus, the compounds of this invention serve as intraperitoneally administerable central nervous system de- 4 pressants and as anti-inflammatory agents via either intraperitoneal or oral administration.

DETAILED DESCRIPTION OF THE INVENTION The following preparative procedures for producing the compounds of this invention are presented for purpose of illustration and are not to be construed as the limiting factors on the proper scope of the disclosed invention. It is recognized that those of average skill in the art, when apprized of the invention herein disclosed will contemplate and be placed in possession of applicants contribution to the extent of its true scope.

EXAMPLE I 2-Phenyl-4-(a,a,a-trifiuoro-m-toluidino)- 5 -pyrimidinecarbonitrile A mixture of 4-chloro-2phenyl-S-pyrimidinecarbonitrile (5.0 grams), a,a,a-trifluoro-m-toluidine (15 milliliters), and ethanol (20 milliliters) was heated under reflux for 1 hour. Chilling of the reaction mixture in ice caused separation of a precipitate which was collected on a filter. The product was recrystallized from ethanol, yield 6.5 grams, M.P. -197 C.

Elemental analysis Calcd for C H F N C, 63.53; H, 3.26; N, 16.46. Found: C, 63.36; H, 3.22; N, 16.71.

EXAMPLE II 2- (p-Tolyl -4- 2,3 -dimethylanilino S-pyrimidinecarbonitrile Reflux a mixture of 4-ch1oro-2-(p-tolyl)-5-pyrimidinecarbonitrile with an equimolar amount of 2,3-dimethylaniline and ethanol for about one hour. Cool the resulting reaction mixture with ice water to obtain the title compound.

EXAMPLE III 6-Methyl-2-phenyl-4-(c n,a-trifluordm-toluidino)- 5-pyrimidinecarbonitrile Reflux a mixture of 4-chloro-6-methyl-2-phenyl-5-pyrimidinecarbonitrile with a slight stoichiometric excess of a,oz,oL-trifiuOIO-m-IO1l1idine and ethanol for about one hour. Quench the product in ice water and recrystallize the product from ethanol to obtain the title compound.

EXAMPLE IV 2-Phenyl-5-(1g-tetrazol-5-yD-4-(u,a,atrifluoro-m-toluidino -pyrimidine Elemental analysis Calcd for C H F N C, 56.40; H, 3.16; N, 25.58. Found: C, 56.22; H, 2.93; N, 25.61.

Similarly, the products of Examples II and III react with sodium azide to produce the corresponding 5-(1H- tetrazol-S-yl) substituted compounds.

When the compounds of the invention are employed as described above they may be administered alone or in combination with pharmacologically acceptable carriers,

the proportion of which is determined by the chosen route in which of administration and standard pharmaceutical practice. For example, they may be administered orally in tablet or capsule form with conventional flavors, diluents, lubricants, disintegrators or binding agents as may be re- 5 quired. They may be administered orally in the form of a solution or they may be injected parenterally. For parenteral administration they may be used in the form of a sterile solution containing other solutes, for example,

R, R and R are members independently selected from the group consisting of H and alkyl of 1 to 7 carbon atoms,

R and R are members independently selected from the group consisting of --H, alkyl of 1 to 7 carbon atoms and perfluoroalkyl of 1 to 7 carbon atoms,

X is a member selected from the group consisting of enough saline or glucose to make the solution isotonic. 10

It is most advantageous to provide the compound as a and dry powder in a suitable container so that it may be ad- N-N mixed with a suitable aqueous vehicle prior to adminis- H nati and pharmaceutically acceptable acid addition salts there- What is claimed is: 15 1. A compound of the formula: 2. The compound which is 2-phenyl-4-(u,u,u-tr1fluorom-toluidino)-5-pyrimidinecarbonitrile.

3. The compound which is Z-phenyI-S-(IE-tetrazol- S-yl)-4-(u,a,a-trifluoro-m-toluidine)pyrimidine.

x References Cited m N I UNITED STATES PATENTS m NR 3,563,984 2/1971 Kim et al. 260-244 25 DONALD G. DAUS, Primary Examiner R. v. RUSH, Assistant Examiner R US. Cl. X.R. 

